Welcome back! If you’ve read our first post Crack Python Basics: Learn Variables the Easy Way you’ve already taken the first step toward mastering Python. Now, with Python variables continued, we’re building on that foundation with slightly more advanced (but still beginner-friendly) concepts that will make your code cleaner, smarter, and easier to manage.
In this continuation, we’ll explore:
- ✅ Assigning multiple values in one line
- 🌍 How global variables work—and when to use them
- 🧩 Naming multi-word variables with PascalCase, snake_case, and camelCase
- 📜 Official rules for naming variables in Python
- 📦 Unpacking lists into multiple variables
- 🔒 Using constants to protect important values
These techniques will help you write more flexible, readable code. Let’s dive in and keep cracking those Python basics!
Assigning Multiple Values at Once
Python lets you assign values to multiple variables in a single line:
x, y, z = 1, 2, 3
Each variable gets its corresponding value. You can also assign the same value to multiple variables:
a = b = c = 0
This is handy when initializing several variables with the same starting value.
Global Variables in Python
Imagine you’re writing a story, and you want the main character’s name to appear in every chapter. Instead of repeating it, you define it once at the top—and every part of your story can use it. That’s how a global variable works.
A global variable is:
- Defined outside of any function
- Accessible from anywhere in your code—including inside functions
counter = 0 # global variable
def increment():
global counter
counter += 1
Without the global keyword, Python treats counter as a new local variable inside the function.
Pros and Cons of Global Variables
Pros:
- Accessible from anywhere
- Great for shared settings (e.g., flags, counters)
- Simplifies small scripts
- Quick to implement
Cons:
- Harder to debug
- Risk of accidental changes
- Reduces modularity
- Increases chance of name conflicts
- Can lead to messy code
Best Practice: Use global variables sparingly. They’re fine for small scripts or shared constants, but for larger projects, steer towards local variables and function parameters to keep your code clean and predictable.
Multi-Word Variable Names: Naming Styles
Python doesn’t enforce a specific style for multi-word variable names, but consistency matters. Here are three common conventions:
| Style | Example | Use Case |
|---|---|---|
| PascalCase | UserProfile | Class names |
| snake_case | user_profile | Variables and functions in Python |
| camelCase | userProfile | Popular in other languages (e.g., JavaScript) |
Tip: Stick with snake_case for variables and functions—it’s the Python community standard.
Python Variable Naming Rules
Here’s a quick checklist to keep your variable names valid:
- ✅ Must start with a letter or underscore (
_) - ❌ Cannot start with a number
- ✅ Can include letters, numbers, and underscores
- 🔍 Case-sensitive:
age,Age, andAGEare different - 🚫 Cannot be a Python keyword (like
for,if,class, etc.)
Want to see all reserved keywords? Try this:
import keyword
print(keyword.kwlist)
Unpacking Lists with Multiple Variable Assignment
Python makes it easy to unpack lists or tuples into variables:
colors = ["red", "green", "blue"]
r, g, b = colors
Each variable grabs one item from the list. You can also use the asterisk * to capture remaining items:
first, *middle, last = [1, 2, 3, 4, 5]
# first = 1, middle = [2, 3, 4], last = 5
This improves readability and avoids manual indexing.
Python Constants: Fixed Values That Speak Loudly
A constant is a variable that’s meant to stay the same throughout your program. Python doesn’t enforce constants, but developers follow a naming convention to signal intent:
Constants are written in ALL CAPS with underscores:
MAX_RETRIES = 5
API_URL = "https://example.com"
PI = 3.14159
This tells anyone reading your code: “This value is important—and it shouldn’t change.”
Why Use Constants?
- Clarity: Descriptive names like
MAX_RETRIESare easier to understand than raw numbers - Consistency: Define once, use everywhere
- Safety: Reduces accidental changes
- Team-friendly: ALL CAPS signals intent to other developers
Important Note: Python won’t stop you from changing a constant—it’s just a convention. So while this is allowed:
MAX_RETRIES = 5
MAX_RETRIES = 10 # Python allows this
…it’s considered bad practice. Treat constants with care and respect.
Best Practices for Constants
Don’t overuse them—keep your code clean and focused
Use ALL CAPS for constants
Define them at the top of your script or in a config file
Only use them for values that truly shouldn’t change
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